Q; I have a heater problem in my 63 Galaxie, the blower motor bench tests good, I have a new resistor board, and voltage to all positions at the switch, but can’t get it to run in the car. Any suggestions?
A; ok, if you have voltage at the black wire on the switch, then you have continuity through the resistor at the 3 points, and the switch. Sounds like you probably need to check the ground. The circuit grounds at the switch, and the dash needs to be grounded to supply the switch with a proper ground. Theoretically the dash should self-ground because its steel mounted to steel. Check the dash mounts on the sides at the base of the dash assembly, install a shake-proof type washer under the head of the mounting bolts to help ground continuity there.